One of Nikonnian members had a conversation with a lens technician at Canon about supposed flair issues with the new 24 – 105 lens, and here’s what the technician said:

“Yes, Canon is aware of a flair problem that is “beyond acceptable limits”.
The problem occurs when a strong light source approximately “37.5 – 45 degress” from the lens corresponds with a wide zoom and wide aperture setting.”

Canon has stopped producing and shipping the 24-105 lenses while they fix the problem. They have also asked dealers to return unsold stock so the problem can be fixed.

They will have parts available on November 15 to fix the problem on lenses that have already been sold. They will, of course, fix the problem at no cost.

They expect a FAST turn-around on repairs since only about 1,500 lenses have made it into the market place and they have multiple service centers.The lens should be returned within 10-14 days.